Round-1 reviewer follow-up to 7031e0d. The brief was explicit
that the test header had to NAME the sibling cgen bug (project
#179, cgmatch flatvariantidx N_TNAME-only gate) — not just
describe its shape. Pre-fix the gap paragraph mentioned the
gate site (selfhost/cmd/wcc/cgenexpr.ww:1512) and the runtime-
masking mechanism, but lacked the literal "#179" handle a
future bisect would grep for. Also folds in the explicit
zero-init-tag-0 masking note (the brief asked for it).
Comment-only — no Makefile, no harness, no row delta.
Hojun-Cho
caca68eb72